In tuberculosis, laryngitis is a frequent occurrence. In most cases it is secondary to the pulmonary affection, and due to the direct influence of the contagious sputum--according to Heinze, however, not to contagion, but to the influence of the infected blood. In other cases it appears to develop spontaneously, before any pulmonary affection is diagnosticated, and may then be due to some poison circulating in either blood or lymph. Tubercular laryngitis, according to Rindfleisch, commences in the excretory ducts of the muciparous glands. That this is so in a great many cases is undoubted. The first changes visible are small cellular subepithelial infiltrations or real subepithelial tubercles, which, while growing, undergo gaseous degenerations and ulcerate. These ulcerations are either flat and small or deeper with an infiltrated edge, and are apt to terminate in secondary nodulated infiltrations and abscesses. Large tumors are not met with, but oedema and phlegmonous inflammations are by no means rare. ETIOLOGY.--The predisposition varies according to individuals, ages, and seasons. Some mucous membranes appear to be more sensitive than others. The hereditary transmission of peculiarities of structure of all or some tissues or organs is apparent, in the case of laryngitis, in the fact that many children in the same family or the children of parents who were sufferers themselves are affected. Children are more liable than adults, infants more than children: 20 per cent. of all the cases are met with under a year, 25 from the first to the second, 15 from the second to the third. Not many occur after the twelfth year. The narrowness of the infant larynx and the looseness of its mucous membrane afford full play to injurious influences, such as dust, cold and moist air, changing temperatures, hot vapors and beverages. Colds, though their nature and effects can hardly be said to be understood, are certainly amongst the main causes. Perspiring surfaces afford frequent opportunities. One of the principal causes is insufficient clothing--more amongst the well-to-do than amongst the poor. The latter have this blessing in their misfortune, that they are protected uniformly if at all, and have their skins hardened by exposure. The bare necks and chests, the exposed knees, the low stockings and thin shoes of the children of the rich, old and young, are just as many inlets of laryngeal catarrh, inflammatory disease, and phthisis. Persons suffering from nasal catarrh or pharyngeal catarrh are liable to have laryngitis. Thus, not only rachitis, with its influence on lymphatic glands and the neighboring mucous membranes, but also acute infectious diseases, such as whooping cough, measles, influenza, erysipelas, hay fever, tuberculosis, syphilis, typhoid fever, and variola, are as many causes of laryngitis. That over-exertion of the voice should produce laryngitis seems probable, but experience does not